Yes, I knew that this would liven things up a bit :-) First of all, my explanation of hidarimae was incorrect. Sorry about that - oyurushi wo ;-) The wrapping of the right side of the kimono /uwagi / haori / happi etc. to the left is the hidarimae version.
I love the different responses - both the light-hearted ones as well as the serious.
I personally like the traditions and protocol that you find in Aikido / Budo. There is a spiritual layer that is to be found in the "kata" of things in the Budo tradition and I find this very fascinating. I understand that some people have more of a pragmatic attitude towards these things and I respect that completely. To each his/her own.
I have asked Isoyama Sensei from the Ibaraki Shibu Dojo about this question and I have received a very good explanation. I will come back with the parts that relate to the subject as soon as I have translated it.
The gist of his reply is that there are differences in the reigi saho of Aikido in comparison to other forms of Budo. Especially the beginning with the left leg when going into seiza etc. is based on the defensive, non-aggresive attitude embodied in the spirit of Aikido. This seems to be his point when stepping with the left leg into the hakama as well.